How Do I Read My Nitrite Chart?

Nitrite, also called NO2, develops in aquarium water as part of the nitrogen cycle. Fish waste contains ammonia, which is neutralized and made safe by a strong colony of beneficial filter bacteria in an established aquarium. A new set up needs at least a month to stabilize and during this time, ammonia combines with bad bacteria, producing nitrite and fish begin to die. You can prevent problems by checking for nitrites with a test kit.

Things You'll Need

  • Nitrite (NO2) test kit
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Instructions

    • 1

      Lay out the contents of the nitrite test kit. The items vary slightly between brands, but typically include a test tube and lid, one or two bottles of nitrite reagent solution and a color coded chart for determining results. Alternatively, you may have a dip strip that provides an instant color-change result on the strip. Test your aquarium water according to the instructions in the kit.

    • 2

      Hold the test tube or dip strip against the nitrite chart and compare the color of the water or strip with the color blocks. You do not require any scientific knowledge to decipher the readings. The blocks are color coded for easy-to-interpret results. Different brands use different colors, but each colored block is clearly labelled within the chart, informing you whether your water is safe, borderline or potentially toxic.

    • 3

      Determine whether you need to take further action. Results in the lowest block, or safe range are acceptable, but you should test again in a day or two to ensure the nitrite does not escalate further. A reading in one of the higher color blocks indicates there is a potentially dangerous level of nitrite in your water. Nitrite is measured in ppm, which stands for parts per million. As a guide, never allow nitrite to reach 0.1 ppm during the nitrogen cycle.

    • 4

      Perform an immediate 50 percent water change if nitrite is high. Your fish will die if you do not reduce toxins quickly. A new tank or one suffering from biological problems is likely to have very high levels, but you can rectify the situation with regular tank maintenance and small, frequent water changes.